The present invention relates to a seat which includes a plurality of portions which can be varied with respect to form and hardness.
Various kinds of seats for a motor vehicle of this type have been proposed in past years. One such seat is disclosed in JP 61-257333. This seat has a side support portion, a center support portion, and a front support portion which include support members therein. The contour of the seat is variable by expanding and contracting each of the support members. In the event of long driving, each of the support members is controlled at a predetermined cycle by a timer so as to vary the contour of the seat. This variation in contour of the seat results in a periodic change in the posture of a seat occupant, decreasing the fatigue of the occupant during driving.
With such a known seat for a motor vehicle, however, since each of the support members is controlled only with a predetermined cyclic pattern which can not be changed, the same cyclic pattern is applied to any seat occupant, causing the seat occupant discomfort in some cases.